Golf club

ABSTRACT

A golf club comprising a golf club head and a shaft assembly. The golf club head has a toe portion and a heel portion with a hole extending inwardly from the upper surface of the golf club head into the heel portion. The shaft assembly has a lower shaft portion that is angularly offset by 7 degrees to 15 degrees from the main elongated shaft portion of the shaft assembly. The lower shaft portion is received in the hole of the golf club head to interconnect the shaft assembly to the golf club head.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to Golf Clubs that offer improvedperformance due to their novel construction. In the golf club of thisinvention, the center axis of the main elongated shaft, when extendedthrough the club head, will pass in close proximity to the center ofpercussion of the golf club head. The lower portion of the main shaft isoffset at an angle from the center axis of the main elongated portion ofthe shaft. A bored hole is provided in the club head which extends intothe heel portion thereof from the upper surface of the club head througha protruding tilted neck. The bored hole in the heel portion receivesthe angularly off-set lower portion of the shaft. As the center axis ofthe lower shaft portion makes a greater acute angle with the horizontalplane or ground level than the center axis of the main elongated shaftwhen the golf club is held in an address position by the golfer, thetilted neck encompassing the bored hole, in which the lower shaftportion is received, can be angled in a more upright position thanprotruding hosels of conventional golf clubs. This achieves a decreasedfrontal surface area for the golf club head which provides a lower dragcoefficient and greater club head speed for longer ball distance.

Further, the golf head of this invention improves the golfer'sperformance due to the reduction in the twisting or torque reaction asthe center axis of the main elongated shaft when extended downward intothe club head passes in close proximity to the center of percussion orcenter of mass of the club head. This decreases the distance of themoment arm of the force applied to the shaft by the golf ball whenstruck by the golf club, thus minimizing the twisting of the golf clubin the golfer's hands. The end result is greater control to hit the golfball in the desired direction due to less slicing or hooking of the golfball.

The inventor, in a co-pending patent application, Ser. No. 633,263 filedDec. 24, 1990, now U.S. Pat. No. 5,197,733, discloses a golf club shaftthat has its lower portion angularly offset from the main elongatedshaft portion but the lower shaft portion is received in a hole thatextends inwardly towards the center of percussion rather than away fromthe center towards the heel portion of the club head as in thisinvention. The angularly offset lower shaft portion, after it isreceived in the hole of the club head but before it is adhesively bondedto interconnect the shaft to the club head, will allow for theadjustment of the face angle of the striking face of the club head byslightly rotating the main shaft. This method of adjustment duringassembly as described in the co-pending patent application, Ser. No.633,263, now U.S. Pat. No. 5,197,733, by the same inventor is stillavailable to be applied to the golf club of this invention even thoughthe lower shaft portion is angled towards the heel rather than towardsthe center of the club head.

2. Description of Prior Art

U.S. Pat. No. 3,966,210 shows a golf club head which has a straightshaft with the center axis thereof extending through the center of theclub head. This prior art patent, though, does not incorporate an angledlower shaft portion or a bored hole extending into the heel of the clubhead to receive a lower shaft portion that is displaced from the centeraxis of the elongated main shaft. U.S. Pat. No. 3,166,320 discloses agolf club that has a bent shaft at the lower end thereof that isreceived in a bored hole in the club head. In this patent, the boredhole is so located to position the lower bent shaft portion towards theback or rear of the club head behind the center of percussion whilemaintaining the center axis of the main elongated shaft forward of thestriking face to achieve a "caster" effect between the shaft and golfclub head.

SUMMARY OF THE PRESENT INVENTION

In the present invention, the golf club head and the shaft are of animproved construction to impart greater accuracy and distance to thegolf ball being impacted by the golf club of this invention being swungby the golfer.

This invention provides an angled lower shaft portion offset from themain elongated shaft portion which, when received in a bored hole in theclub head, is directed towards the heel portion thereof. Because of theoffset of the lower shaft portion being received in the heel portion,the main elongated shaft in relation to the club head can be positionedso that the lower segment of the main elongated shaft portion is movedcloser to the center of the club head. The center axis of the mainelongated shaft portion when extended downward into the club head passesin close proximity to the center of percussion of the club head. Thisreduces the torque factor of the golf club when striking the golf ballas the center of percussion which represents the center of mass of theclub head, is at a decreased normal distance from the center axis of themain elongated shaft portion of the golf club to which the force isapplied. The neck encompassing the upper part of the bored hole in theclub head can be tilted in a more upright direction as the co-axialcenter axis of the hole and the lower shaft portion received thereinmake a greater acute angle with the ground level than the center axis ofthe main shaft which is usually maintained at about 55 degrees. As aresult, the frontal surface area of the club head is decreased with theinherent advantage of minimizing the air drag coefficient.

One objective of this invention is to minimize twisting of the golf clubin the hands of the golfer when he swings the golf club which reducesslicing or hooking of the golf ball.

Another objective of this invention is to achieve a lower dragcoefficient for the club head due to a decrease in frontal surface areaof the club head.

Another objective of this invention is to achieve a specific golf clubstructure that incorporates an angularly offset lower shaft portionreceived in an angled bored hole to allow for the application of themethod of adjustment and assembly to the golf club of this invention asdescribed in co-pending patent application Ser. No. 633,263 by the sameinventor.

These and other objectives will become more apparent with reference tothe accompanying drawings and following specifications:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a golf club head and a portion of the shafttherefore embodying the teachings of this invention,

FIG. 2 is a frontal view of the golf club head and a portion of theshaft of FIG. 1,

FIG. 3 is a frontal view, partially in section taken along line 3--3 ofFIG. 1, and

FIG. 4 is a cross-sectional view of a lower part of the shaft assemblyincorporating an alternative embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2, and 3, a golf club 11 comprising a golf clubhead 12 and a shaft assembly 13 of this invention is depicted. The shaftassembly 13 is provided with a lower shaft portion 14 and a mainelongated shaft portion 15. In the drawings, the golf club 11 is notshown in its entirety as the invention mostly encompasses themodification to the club head 12 and the lower portion 14 of the shaftassembly 13. The main elongated shaft portion 15 extends upwardly andterminates in a conventional grip (not shown) to allow the golfer tograsp and swing the golf club 11. The preferable golf club head 12 ofthis invention is a driver, also called a "wood", can be cut from asolid block such as persimmon, or laminated wood, or manufactured out ofmetal or plastic.

The club head 12 has a toe portion 16 and a heel portion 17 integrallyformed with an upper surface 18 contiguous with the heel portion 17 andthe toe portion 16. A generally convex-curved striking face 19 isprovided at the frontal surface of the club head 12. An insert 21,usually fabricated from a high energy material, is recessed into thestriking face 19. The club head 12 has a rear portion 22 opposite thestriking face 19. A sole plate 23 as best seen in FIG. 2, is mounted tothe bottom surface of the club head to protect the club head 12 when itmakes contact with the earth or grass at ground level 24.

Each club head 12 has a center of percussion 25 at the point where thecenter of mass is located. The "sweet spot" 26 shown in FIG. 2 by adotted circle is the center of percussion 25 transposed to the strikingface 19 at its, forwardmost point 27 which is substantially at thecenter thereof. Each golfer, upon swinging the golf club 11, tries toimpact the golf ball as close to the "sweet spot" 26 as possible toobtain optimum distance and accuracy.

In FIGS. 1, 2, and 3, the preferred embodiment of this invention isshown. The club head 12 is provided with a short neck 28 extending in anangular upward direction from the upper surface 18 at its heel portion17. A metal ring 29 could be placed around the neck 28 to providereinforcement if needed. The neck 28 encompasses the upper end of abored hole 31 that extends inwardly from the top of the neck 28 into theheel portion 17 of the club head 12 at an angle of about 65 degrees withthe horizontal ground level 24 when the golf club 11 is held in anaddress position by the golfer. The angle could range from 60 70 degreesdepending on the configuration of the club head 12. In an addressposition, the main elongated shaft portion 15 is usually held by thegolfer at an angle of about 55 degrees with the ground level 24 with theclub head 12 resting on the ground behind the golf ball. The directionof the hole 31 bored into the heel portion 17 of the club head 12 isselected so that the center axis 32 of the hole 31 and the co-axialcenter of axis 33 of the lower shaft portion 14 when received in thehole 31 lie in a vertical plane that is substantially parallel with asecond vertical plane extending through a horizontal line 34 which istangent to the forwardmost part 27 of the striking face 19,substantially at its center or at the "sweet spot" 26 as seen in FIG. 1.

The center axis 33 of the lower shaft portion 14 is offset by an angleranging from 7 degrees to 15 degrees from the center axis 35 of the mainelongated shaft portion 15. The center axis 35, if extended downwardlyinto the club head 12, usually makes an angle of about 55 degrees withthe ground level 24 when the golf club 11 is held in an address positionby the golfer. As seen in FIG. 2, the extended axis 35 of the mainelongated shaft portion 15 passes closer to the center of percussion 25when measured along a straight line perpendicular to the axis 35 thanwould be the case with conventional golf clubs having protruding hosels.

In FIGS. 1, 2, and 3, the preferred embodiment of this invention showsthat the lower shaft portion 14 of the shaft assembly 13 comprises astub shaft 37 and a sleeve 38 encompassing the stub shaft 37. As bestseen in FIG. 3, the sleeve 38 can be made out of metal tubing thatslides onto the stub shaft 37. The stub shaft 37 could also be madeintegrally with or be an extension of the main elongated shaft portion15 of the shaft assembly 13. The lower segment of the sleeve 38 receivedonto the stub shaft 37 can be bent together with the stub shaft 37 to beangularly offset from the main elongated shaft portion 15 so as to serveas the lower shaft portion 14 that is received in hole 31 in the clubhead 12. The sleeve 38 extends above the stub shaft 37 to also encompassthe lower end of the main elongated shaft portion 15 to protect theshaft assembly 13 at bend 36 when it is fabricated. By bending the lowerend of the main elongated shaft portion 15 and the sleeve 38 together atone time, these pieces become interlocked to form an integral, unitarystructure. Although the sleeve 38 is the preferred embodiment of thisinvention, it is not absolutely required as the lower shaft portion 14and the main elongated shaft portion 15 can be bent from a singularstraight metal shaft with the angular offset lower shaft portion 14received in the bored hole 31.

To interconnect the shaft assembly 13 to the golf club head 12, anadhesive is applied to the surface of the lower shaft portion 14 or, asin the case of the preferred embodiment, to the surface of the sleeve38. Then, the lower shaft portion 14 or the lower segment of the sleeve38 is positioned so as to be received wholly or partially in the boredhole 31 and held in a fixed position until the adhesive has set up.

In FIG. 4, a further embodiment of this invention is illustrated inwhich the lower part of the shaft assembly 13 incorporates analternative construction. At times, the main elongated shaft portion 15is fabricated from boron or graphite or some other material that cannotbe bent. To accommodate this possibility, the construction of a shaftassembly 39 shown in FIG. 4 has been developed to duplicate the functionof the lower shaft portion 14 as previously described and seen in FIG.2. As seen in FIG. 4, a sleeve 41 or steel tubing is bent so that thecenter axis 42 of an upper portion 43 of the sleeve 41 is angularlydisplaced from the center axis 44 of a lower portion 45 of the sleeve 41by about 7° to 15 degrees. The upper portion 43 of the sleeve 41receives the bottom segment of the main elongated shaft portion 15 whichis bonded into the upper portion 43. The lower portion 45 of the sleeve41 is received in bored hole 31 of the club head 12 as seen in FIGS. 1,2, and 3, and adhesively bonded thereto to achieve the interconnectionof the shaft assembly 13 to the golf club head 12.

While only the preferred embodiments of the present invention have beendescribed, others may be possible without departing from the scope ofthe appended claims.

I claim:
 1. A golf club comprising a golf club head and a shaftassembly, said golf club head having a toe portion, a heel portion, acenter of percussion substantially in the center of said club head, anupper surface contiguous with said toe portion and said heel portion,and a bored hole extending inwardly from said upper surface into saidheel portion in an angular direction away from said center ofpercussion, said shaft assembly comprising a main elongated shaftportion and a lower shaft portion, the center axis of said lower shaftportion being angularly offset from the center axis of said mainelongated shaft portion by an angle ranging from 7 to 15 degrees, and atleast a part of said lower shaft portion being received in said boredhole, said main elongated shaft portion remaining exterior of said clubhead, the center axis of said main elongated shaft portion when extendeddownwardly into said club head passing in close proximity of said centerof percussion.
 2. A golf club comprising a golf club head and a shaftassembly, said golf club head having a toe portion, a heel portion, anupper surface contiguous with said toe portion and said heel portion, acenter of percussion substantially at the center of said club head, anda bored hole extending inwardly from said upper surface into said heelportion in a direction away from said center of percussion, said shaftassembly comprising a main elongated shaft portion terminating in abottom segment at one end thereof, and a sleeve, said sleeve having anupper portion and a lower portion, said lower portion being angularlyoffset from said main elongated shaft portion by an angle ranging from 7to 15 degrees, said bottom segment of said main elongated shaft portionbeing received in said upper portion of said sleeve, said upper portionbeing external of said club head, the center axis of said main elongatedshaft portion and said upper portion when extended downwardly into saidclub head passing in close proximity of said center of percussion, saidlower portion of said sleeve being received in said bored hole tointerconnect said shaft assembly to said golf club head.
 3. A golf clubcomprising a golf club head and a shaft assembly, said golf club headhaving a toe portion, a heel portion, an upper surface contiguous withsaid toe portion and said heel portion, a convex-curved striking face,and a bored hole extending inwardly from said upper surface into saidheel portion, said striking face having a forwardmost part at the centerthereof, said shaft assembly comprising a main elongated shaft portionand a lower shaft portion, the center axis of said lower shaft portionangularly offset from the center axis of said main elongated shaftportion by an angle ranging from 7 to 15 degrees, at least a part ofsaid lower shaft portion being received in said bored hole tointerconnect said shaft assembly to said club head, said main elongatedshaft portion remaining exterior of said club head, the center axis ofsaid main elongated shaft portion when extended downwardly into saidclub head passing close to the center of said club head, the center axisof said lower shaft portion lying in a vertical plane to substantiallyparallel with a second vertical plane passing through a horizontal linetangent to said forwardmost part of said striking face.
 4. A golf clubas defined in claim 3 wherein said shaft assembly has a stub shaftintegrally formed with said main elongated shaft portion, and a sleeve,said sleeve encompassing said stub shaft, said sleeve and said stubshaft being bent to angularly offset said lower shaft portion from saidmain elongated shaft portion.
 5. A golf club as defined in claim 3wherein a neck having an upper periphery extends upwardly at an anglefrom said upper surface at the heel portion of said golf club head, saidbored hole extending through said neck into said heel portion of saidgolf club head, the center axis of said neck being substantiallyco-axial with the center line of said bored hole and said lower shaftportion received therein.
 6. A golf club as defined in claim 5 wherein aring encompasses the upper periphery of said neck.
 7. A golf club asdefined in claim 3 wherein said shaft assembly includes a sleeve, saidsleeve encompassing said lower shaft portion and a segment of said mainelongated shaft portion.
 8. A golf club as defined in claim 7 whereinsaid sleeve and said lower shaft portion are bent together to provide anintegral, unitary structure. .Iadd.
 9. A golf club comprising a golfclub head and a shaft assembly, the golf club head having a toe portion,a heel portion, a center of percussion substantially in the center ofthe club head, an upper surface contiguous with the toe portion and theheel portion, and a hole extending inwardly from the upper surface intothe heel portion in an angular direction away from the center ofpercussion, the shaft assembly further comprising a main elongated shaftportion and a lower shaft portion, the center axis of the lower shaftportion being angularly offset from the center axis of the mainelongated shaft portion, and at least a part of the lower shaft portionbeing received in the hole, the main elongated shaft portion remainingexterior of the club head, the center axis of the main elongated shaftportion, when extended downwardly into the club head, passing in closeproximity of the center of percussion. .Iaddend..Iadd.10. A golf clubcomprising a golf club head and a shaft assembly, the golf club headhaving a center of percussion substantially in the center of the clubhead, and a hole extending inwardly into a heel portion of the club headin an angular direction away from the center of percussion, the shaftassembly further comprising a main shaft portion and a lower shaftportion, the center axis of the lower shaft portion being angularlyoffset from the center axis of the main elongated shaft portion, and atleast a part of the lower shaft portion being received in the hole, themain shaft portion remaining exterior of the club head, the center axisof the main shaft portion, when extended downwardly into the club head,passing in close proximity of the center of percussion..Iaddend..Iadd.11. A method for interconnecting a golf club head and agolf club shaft, the golf club head having a center of percussionsubstantially in the center of the club head, the method comprising thefollowing steps:1. forming a hole extending inwardly into a heel portionof the club head in an angular direction away from the center ofpercussion;
 2. forming a sleeve, the center axis of a lower portion ofthe sleeve being angularly offset from the center axis of an upperportion of the sleeve;
 3. receiving into the hole at least a part of thelower portion of the sleeve;4. receiving into the upper portion of thesleeve a lower portion of the shaft;whereby the center axis of the shaftwhen extended downwardly into the club head passes in close proximity tothe center of percussion. .Iaddend.